For producing a vapor deposited film, an evaporating machine as shown in FIG. 16 is used. In the evaporating machine 1, a base film 12 is set on a film unwinder 11 installed in a vacuum chamber 10, and the film 12 is carried through a plurality of rollers of a carrier system 13 and a cooling roller 14, being wound around a winder 15.
While being carried, margin zones are formed on the film 12 as metal vapor nondeposited zones formed continuously in the machine direction at predetermined positions in the transversal direction by a margin forming device 16, and furthermore, has metal vapor deposited zones formed continuously in the machine direction at predetermined positions alternately with said margin zones in the transversal direction by a metal evaporator 17 installed below the cooling roller 14. In FIG. 16, symbol 18 denotes a viewing window, for viewing by operator 20., formed in the vacuum chamber 10, and 19 denotes a vacuum exhaust port formed in the vacuum chamber 10.
As a result, as shown in the cross sectional views in the transversal direction of FIGS. 17 and 18 for example, the film 12 has a vapor deposition pattern formed. In FIG. 17, the film 12 has metal vapor deposited zones 12a and metal vapor non-deposited margin zones 12b formed on it. In FIG. 18, heavy edges 12c, which are thicker in vapor deposited film thickness, are formed on vapor deposited zones 12a, in addition to the vapor deposited zones 12a and the margin zones 12b. The heavy edges 12c allow easier deposition of sprayed metal in the electrode forming step of capacitor production on the vapor deposited film.
Furthermore, the margin zones 12b are formed by masking the positions corresponding to the margin zones 12b when the metal evaporated from the metal evaporator 17 is deposited on the film 12. The masking can be achieved by applying oil or tape to the positions corresponding to the margin zones using the margin forming device 16 before metal deposition.
In this step of vapor deposition, the positions and widths of the vapor deposited zones and vapor nondeposited zones in the transversal direction of the film can vary when the film carrier system or margin forming device faults or when the film is uneven in thickness, and the variation greatly affects the quality of the vapor deposited film. Therefore, in the production of the vapor deposited film, the positions and widths of deposition must conform to specified values.
For this reason, in the conventional technique, the film carrier system 13 and the margin forming device 16 must be sufficiently maintained to keep the positions and widths of the vapor deposited zones and margin zones constant. Moreover, during the step of evaporation, the operator 20 observes the vapor deposited film 12 immediately after vapor deposition through the viewing window 18, and adjusts the film carrier system 13 to keep the film 12 traveling stably and adjusts the margin forming device 16 to maintain the positions and widths of the margin zones at the specified values.
If the heavy edges 12c are to be formed, they must be located at the centers of the vapor deposited zones 12a in the transversal direction of the film since the heavy edges 12c correspond with the electrode forming portions in the production of capacitors.
Hence, in the conventional technique, the relative position of the margin forming device 16 and the metal evaporator 17 to form the heavy edges in the transversal direction of the film are adjusted to keep the centers of the heavy edges 12c in agreement with the centers of the vapor deposited zones 12a held between the margin zones 12b, before metal evaporation. Furthermore, during the step of evaporation, the operator 20 observes the vapor deposited film 12 immediately after evaporation through the viewing window 18, and finely adjusts the margin forming device 16 or the metal evaporator 17 to keep the central positions of the heavy edges 12c in agreement with the central positions of the vapor deposited zones 12a.
In the above conventional technique, since the positions and widths of the margin zones are manually adjusted to conform to the specified values, the system disadvantageously relies on the skill of the operator. In particular, it is not easy to train the operator to make dimensional adjustments based on recognition of slight deviations.
Moreover, if the cause for the deviation in the positions and widths of the margin zones cannot be identified soon, uncontrollable deviation can occur, thereby lowering efficiency to a great extent before a skilled operator can take any effective measure.
In addition, the position adjustment of the heavy edges also requires a high degree of skill to achieve a good result.
For these reasons, the vapor deposited film thus prepared is liable to be unstable in the dimensions and positions of the vapor deposited zones and vapor nondeposited zones. As a result, the capacitors, etc. to which such a vapor deposited film is applied can suffer from dispersed electrostatic capacity or low reliability.